The proposed research will investigate the short term respiratory effects of formaldehyde exposure in naive subjects. The design will utilize the periodic controlled formaldehyde exposures which graduate students in clinical anatomy experience during cadaver dissection and observation. The study design addresses several limitations of many epidemiologic studies of respiratory irritants, by: providing individual quantitative estimates of formaldehyde lung dose, studying subjects with no significant prior history of exposure, collecting large numbers of measures of symptom intensity and pulmonary function on the same group of subjects exposed repeatedly to formaldehyde, and gathering data on individual sensitivity by methacholine challenge and skin prick testing for atopy. A pilot study in the clinical anatomy laboratory at the University of Massachusetts at Lowell in the fall of 1990 detected significant decrements in peak expiratory flow (PEFR) across the three hour laboratory periods in the 24 students monitored. Students also exhibited a small but statistically significant decline in baseline PEFR over the course of a ten week observation period in which they were exposed for one three-hour lab session each week. This two year investigation would be conducted in the same environment as the pilot, but with a more elaborated study design allowing quantitative lung dose estimation and more precise lung function assessment. Approximately 60 subjects would be followed during fourteen weeks of exposure for three hours each week. Full spirometry would be performed at the beginning and end of this period, and peak flow measurements would be performed throughout. Individual formaldehyde exposure estimates for all exposure periods would be made. A model of formaldehyde lung dosimetry used by the U.S. EPA would be adapted to provide estimates of individual lung dose for quantitative dose response studies.